The reaction of primary phosphines and aldehydes to give a variety of products depending upon the nature of the substituent of the primary phosphine, the type of aldehyde and the presence of acid, is known. For example, primary aromatic or aliphatic phosphines react with formaldehyde in the presence of aqueous hydrochloric acid to give hydroxymethylphosphonium salts (Angew Chem. 72 211 [1960]); ##STR1##
Phenyl phosphine and a) acetaldehyde or b) benzaldehyde, in the presence of hydrochloric acid, is reported to give a) phenyl bis(alpha-hydroxyethyl) phosphine and b) phenyl bis(alpha-hydroxybenzyl)phosphine (CA 57: 4692e [1962]); ##STR2## while phenylphosphine and isobutyraldehyde, in hydrochloric acid solution, gives an alpha-hydroxyalkyl phosphine hydrochloride (Tetrahedron 18, 1231 [1962]). ##STR3##
Furthermore, phenyl phosphine when reacted with benzaldehyde will give three different products depending on the conditions and strength of the hydrochloric acid used, ##STR4##
The reaction of phosphine and dialdehydes is reported to give spirocyclic phosphonium compounds of the formula; ##STR5## The authors noted that "attempts to prepare an analogous spiran by reaction with glyoxal were unsuccessful".
The J. Org. Chem. 35 (8) 2820 (1970) discloses the preparation of 2,5-dialkoxy-1,4-diphosphorinane-1,1,4,4-tetraphenyl, onium bromide, by the reaction of lithium diphenyl phosphide and chloroacetaldehyde, acetal followed by reaction with hydrogen bromide in acetic acid; ##STR6##
In CA 88: 5097d [Z. Chem. 17 (10) 365 (1977)] there is disclosed the preparation of 2,5-dihydroxy-1,1,4,4-tetraphenyl-1,4-diphosphorinonium dichloride by the reaction of the above phosphine with dilute hydrochloric acid; ##STR7##
U.S. Pat. No. 3,206,496 (9/14/65) discloses the preparation of 1,4,diphosphorinonium salts by the reaction of a secondary phosphine and vinyl halides; ##STR8## While U.S. Pat. No. 2,931,803 (4/5/60) teaches the preparation of fluorocarbon-containing 1,4-diphosphorinanes, 1,4-diiodides, prepared by the reaction of tetrafluoroethylene, elemental phosphorus, and iodine; ##STR9## It is further disclosed that hydrolysis of above type heterocyclic followed by oxidation results in the formation of open-chain phosphonic acids. However, all above prior art diphosphorinanes are salts and are therefore totally different from the diphosphorinanes of the instant invention, and in addition are prepared by synthetic routes entirely different than the process of this invention.